Compression stress induces nucleus pulposus cell autophagy by inhibition of the PI3K/AKT/mTOR pathway and activation of the JNK pathway
Compression stress induces nucleus pulposus cell autophagy by inhibition of the PI3K/AKT/mTOR pathway and activation of the JNK pathway
复制标题
压缩应激通过抑制 PI3K/AKT/mTOR 通路和激活 JNK 通路诱导髓核细胞自噬
DOI：
10.1080/03008207.2020.1736578
复制
发表时间：
2020-03-18
影响因子：
2.9
通讯作者：
Ma, Kaige
中科院分区：
文献类型：
--
作者：
Li, Zhiliang;Wang, Jun;Ma, Kaige
目的：活性氧（ROS）与压缩应力诱导的髓核（NP）细胞自噬有关，但其在压缩应力诱导的椎间盘退变（IVDD）中的具体机制尚不清楚。在这里，我们讨论了具体的分子机制，并探讨ROS清除剂是否可以作为抑制压缩应力诱导的IVDD的特异性药物。方法：将大鼠NP细胞置于1.0 MPa压力下，用活性氧清除剂n -乙酰半胱氨酸（NAC）或jnk选择性抑制剂SP600125 not进行预处理。通过共聚焦显微镜监测细胞内ROS的产生。透射电镜观察NP细胞超微结构特征，流式细胞术检测自噬空泡。western blotting分析自噬相关分子、JNK通路和PI3K/AKT/mTOR通路的表达水平。结果：大鼠NP细胞压缩介导的自噬参与了ROS的产生。活性氧清除剂NAC可以通过抑制活性氧的产生来保护压缩诱导的NP细胞损伤。而JNK抑制剂SP600125可减弱压缩诱导的NP细胞自噬。此外，这是第一次有报道表明，压缩通过阻碍压缩诱导的ROS依赖性PI3K/AKT/mTOR通路和ROS依赖性JNK通路的激活，诱导大鼠NP细胞自噬。JNK通路参与的作用机制不同，当被抑制时导致细胞死亡增加，ROS生成增加，但自噬减少。结论：这些结果揭示了ros介导的大鼠NP细胞自噬的新调控机制，可能为改善压迫应力诱导的IVDD的药物开发提供思路，并有助于避免IVD疝的最终手术治疗。
ABSTRACT Purpose: Reactive oxygen species (ROS) are related to compression stress-induced nucleus pulposus (NP) cell autophagy, but the specific mechanism is unknown in compression stress-induced intervertebral disc degeneration (IVDD). Here, we discuss the specific molecular mechanism and explore whether ROS scavengers could be employed as specific drugs to inhibit compression stress-induced IVDD. Methods: Rat NP cells were exposed to 1.0 MPa compression and pretreatment with the ROS scavenger N-acetylcysteine (NAC) or the JNK-selective inhibitor SP600125 not. Intracellular ROS production was monitored by confocal microscopy. Autophagy was detected by observing the NP cell ultrastructural features using TEM and examining autophagic vacuoles by flow cytometry. The levels of autophagy-associated molecules, the JNK pathway and the PI3K/AKT/mTOR pathway were analyzed by western blotting. Results: Compression-mediated autophagy in rat NP cells was implicated in ROS generation. The ROS scavenger NAC could protect compression-induced NP cell injures by inhibiting ROS production. And SP600125, a JNK inhibitor, attenuated compression-induced NP cell autophagy. Additionally, this is the first report showing that compression induces autophagy in rat NP cells by impeding the compression-induced ROS dependent PI3K/AKT/mTOR pathway and the ROS independent activation of JNK pathway. And the involvement of JNK pathway was in different mechanism of action that when inhibited leaded to increased cell death, increased generation of ROS but decreased autophagy. Conclusions: These results show a new regulatory mechanism involving ROS-mediated autophagy in rat NP cells, which may provide ideas for drug development to improve compression stress-induced IVDD and help avoid eventual surgical treatment of IVD herniation.